void main(){
  int n1=10;
  n1+=5;
  print(n1);

  n1-=5;
  print(n1);
  n1*=5;
  print(n1);


//   注意 /=  double类型的数据才能做除等于的操作
  double n2 =50;
  n2/=5;
  print(n2);
  // 取余数
int n3 = 10;
n3%=3;
print(n3);

int a = 10;
a++;
print(a);

int b =20;
b--;
print(b);








}